The present invention relates to a method for the orderly supply of randomly received products.
The present invention is particularly advantageous for supplying food products in general, and confectionary in particular, to a wrapping machine, to which application the following description refers purely by way of example.
Food product manufacturing and packing systems are known to employ wrapping machines, each of which receives the products for wrapping in an orderly, i.e. equally spaced, succession; and dispensing devices, each of which supplies the products either in randomly aligned fashion, or in an orderly arrangement, e.g. in batches, other than that required by the wrapping machine connected to the dispensing device. As such, the arrangement of the products must be adjusted as they are transferred from the dispensing device to the follow-up wrapping machine.
The same also applies in the case of a dispensing device designed to supply the products arranged as required by the wrapping machine, if the orderly sequence with which the products are supplied is interrupted by temporary stoppage of the dispensing device or by rejection of one or a group of products in the sequence.
Italian Patent No. 797,350 and European Patent No. 433,231 relate to methods for the orderly supply of randomly received products to a follow-up machine, and which comprise the steps of conveying a succession of products by means of a first conveying device traveling in a given direction at a first speed, and comprising a first conveying portion of variable length extending between a loading station and a movable transfer station; conveying an orderly succession of products by means of a second conveying device traveling in said given direction at a second speed, and comprising a second conveying portion of variable length complementary to the length of the first conveying portion, the second conveying portion extending between the movable transfer station and an unloading station; and varying the lengths of the two conveying portions by means of an adjusting device, and as a function of the succession of products on the first conveying device and the difference between the first and second speed.
The above methods provide for ordering both a succession of randomly received products and an orderly (equally spaced) succession with missing products, but present the drawback of subjecting the products to frequent slippage in said given direction, both during transfer from the first to the second conveying device, and as the products travel along the conveying portions of the conveying devices. Which slippage obviously results in each product eventually slipping out of position, and the smaller the supporting surface of the product is in relation to its overall mass, the greater the position error is.
Such slippage mainly occurs at the transfer station when the product is positioned astride the first and second conveying device, and is therefore supported partly by the first and partly by the second conveying device normally traveling at different speeds. As a result, the product is subjected to differing amounts of thrust, which in turn results in slippage on the first or second or on both the conveying devices, and in either case in incorrect positioning of the product on the second conveying device.